Fix warnings on Win64.

src/disassembler.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 56 matching lines @@
 const char* V8NameConverter::NameOfAddress(byte* pc) const {
   static v8::internal::EmbeddedVector<char, 128> buffer;
 
   const char* name = Builtins::Lookup(pc);
   if (name != NULL) {
     OS::SNPrintF(buffer, "%s  (%p)", name, pc);
     return buffer.start();
   }
 
   if (code_ != NULL) {
-    int offs = pc - code_->instruction_start();
+    int offs = static_cast<int>(pc - code_->instruction_start());
     // print as code offset, if it seems reasonable
     if (0 <= offs && offs < code_->instruction_size()) {
       OS::SNPrintF(buffer, "%d  (%p)", offs, pc);
       return buffer.start();
     }
   }
 
   return disasm::NameConverter::NameOfAddress(pc);
 }
 
@@ skipping 194 matching lines @@
       } else {
         out.AddFormatted("    ;; %s", RelocInfo::RelocModeName(rmode));
       }
     }
     out.AddString("\n");
     DumpBuffer(f, out.Finalize());
     out.Reset();
   }
 
   delete it;
-  return pc - begin;
+  return static_cast<int>(pc - begin);
 }
 
 
 int Disassembler::Decode(FILE* f, byte* begin, byte* end) {
   V8NameConverter defaultConverter(NULL);
   return DecodeIt(f, defaultConverter, begin, end);
 }
 
 
 // Called by Code::CodePrint.
 void Disassembler::Decode(FILE* f, Code* code) {
   byte* begin = Code::cast(code)->instruction_start();
   byte* end = begin + Code::cast(code)->instruction_size();
   V8NameConverter v8NameConverter(code);
   DecodeIt(f, v8NameConverter, begin, end);
 }
 
 #else  // ENABLE_DISASSEMBLER
 
 void Disassembler::Dump(FILE* f, byte* begin, byte* end) {}
 int Disassembler::Decode(FILE* f, byte* begin, byte* end) { return 0; }
 void Disassembler::Decode(FILE* f, Code* code) {}
 
 #endif  // ENABLE_DISASSEMBLER
 
 } }  // namespace v8::internal